Blowing agent compositions of hydrochlorofluoroolefins

ABSTRACT

The present invention relates to foam products made with blowing agent compositions comprising at least one hydrochlorofluoroolefin (HCFO) used in the preparation of Namable thermoplastic compositions. The HCFOs of the present invention include, but are not limited to, 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd), particularly the trans-isomer, 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), dichloro-fluorinated propenes, and mixtures thereof. The blowing agent compositions of the present invention are used with coblowing agents including carbon dioxide, atmospheric gases, hydrofluorocarbons (HFC), hydrofluoroolefins (HFO), alkanes, hydrofluoroethers (HFE), and mixtures thereof. Preferred HFCs used as coblowing agents in the present invention include, but are not limited too, 1,1,1,2-tetrafluoroethane (HFC-134 a ), 1,1-difluoroethane (HFC-152 a ), 1,1,1-trifluoroethane (HFC-143 a ), pentafluorethane (HFC-125), difluoromethane (HFC-32). The blowing agent compositions are useful in the production of low density insulating foams with improved k-factor.

The present application is a continuation-in-part of application of U.S.patent application Ser. No. 13/342,307 filed Jan. 3, 2012 which claimedpriority to U.S. patent application Ser. No. 12/532,253 filed Sep. 21,2009 which claimed priority to International patent application serialnumber PCT/US08/58596 tiled Mar. 28, 2008 which claimed priority to U.S.provisional patent application Ser. No. 60/908,762 filed Mar. 29, 2007.

SUMMARY OF INVENTION

The present invention relates to blowing agent compositions comprisingat least one hydrochlorofluoroolefin (HCFO) used in the preparation offoamable thermoplastic compositions. The HCFOs of the present inventioninclude, but are not limited to, 1-chloro-3,3,3-trifluoropropene(HCFO-1233zd), particularly the trans-isomer,2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), dichloro-fluorinatedpropenes, and mixtures thereof. The blowing agent compositions of thepresent invention are preferably used with coblowing agents includingcarbon dioxide, atmospheric gases, hydrofluorocarbons (HFC),hydrofluoroolefins (HFO), alkanes, hydrofluoroethers (HFE), and mixturesthereof. Preferred HFCs used as coblowing agents in the presentinvention include, but are not limited too, 1,1,1,2-tetrafluoroethane(HFC-134a); 1,1-difluoroethane (HFC-152a); 1,1,1-trifluoroethane(HFC-143a); pentafluorethane (HFC-125); and difluoromethane (HFC-32).The blowing agent compositions are useful in the production of lowdensity insulating foams with improved k-factor.

BACKGROUND OF INVENTION

With the continued concern over global climate change there is anincreasing need to develop technologies to replace those with high ozonedepletion potential (ODP) and high global warming potential (GWP).Though hydrofluorocarbons (HFC), being non-ozone depleting compounds,have been identified as alternative blowing agents tochlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) in theproduction of thermoplastic foams, they still tend to have significantGWP.

It was discovered that blowing agent compositions comprising ahydrochlorofluorolefin, particularly HCFO-1233zd, HCFO-1233xf,dichloro-fluorinated propenes, and mixtures thereof can permit theproduction of lower density, closed-cell foam and good k-factor whichwill be particularly useful for thermal insulating foams. This inventionmay also permit the production of low density, closed-cell foams withenlarged, controlled cell size.

WO 2004/037913, WO 2007/002703, and US Pat. Publication 2004119047discloses blowing agents comprising halogenated alkenes of genericformula that would include numerous HCFOs, among many other materialsincluding brominated and iodinated compounds and HFOs. Specific HCFOsfor use in thermoplastic foaming are not disclosed nor are the benefitsof using the HCFOs in terms of increasing the foam cell size asdiscovered in the present invention. HCFO-1233zd is disclosed for use inpolyurethane foaming, however it is not obvious to one skilled in theart that a blowing agent for polyurethane foaming would be particularlygood for thermoplastic foaming.

GB 950,876 discloses a process for the production of polyurethane foams.It discloses that any suitable halogenated saturated or unsaturatedhydrocarbon having a boiling point below 150° C., preferably below 50°C., can be used as the blowing agent. Trichlorofluoroethene,chlorotrifluoroethene, and 1,1-dichloro-2,2-difluoroethene are disclosedin a list of suitable blowing agents. Hydrochlorofluoropropenes are notspecifically disclosed nor are longer chain HCFOs, There is nodisclosure related to blowing agents for thermoplastic foaming nor arethe benefits of HCFOs in thermoplastic foaming mentioned nor preferredcombinations of HCFOs with other coblowing agents.

CA 2016328 discloses a process for preparing closed-cell, polyisocyanatefoam. Disclosed are organic compound blowing agents includinghalogenated alkanes and alkenes, where the alkene is propylene, and thehalogenated hydrocarbons can be chlorofluorocarbons. Among the manyexemplary compounds listed are specific chlorofluoroethylenes containing1 chlorine and from 1 to 3 fluorines. Hydrochlorofluoropropenes are notspecifically disclosed nor are longer chain HCFOs. There is nodisclosure related to blowing agents for thermoplastic foaming nor arethe benefits of HCFOs in thermoplastic foaming mentioned nor preferredcombinations of HCFOs with other coblowing agents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plot of total blowing agent content versus foam density forexamples 21 through 50

FIG. 2 is a plot of total blowing agent content versus foam density forexamples 51 through 62.

FIG. 3 is a plot of total blowing agent content versus foam density forcomparative examples 63 through 65.

DETAILED DESCRIPTION OF INVENTION

The present invention relates to the use of blowing agents withnegligible ozone-depletion and low GWP comprising ahydrochlorofluoroolefin (HCFO) used with an additional blowing agent.The present invention discloses blowing agent and foamable resincompositions useful for the production of foams with decreased density,enlarged cell size, and improved k-factor that can be used as insulatingfoams. In a preferred embodiment of this invention the HCFO is1-chloro-3,3,3-trilfluoropropene (HCFO-1233zd), preferably the transisomer; 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), and mixturesthereof. Preferred coblowing agents to be used with the HCFO includehydrofluorocarbons (HFC), preferably 1,1,1,2-tetrafluoroethane;1,1-difluoroethane (HFC-152a); pentafluoroethane (HFC-125);1,1,1-trifluoroethane (HFC-143a); difluoromethane (HFC-32);hydrofluoroolefins (HFO), preferably 3,3,3-trifluoropropene(HFO-1243zf); 1,3,3,3-tetrafluoropropene (HFO-1234ze), particularly thetrans isomer; 2,3,3,3-tetrafluoropropene (HFO-1234yf); (cis and/ortrans)-1,2,3,3,3-pentafluoropropene (HFO-1225ye); carbon dioxide;alkanes, preferably a butane or a pentane, and mixtures thereof.

Another embodiment of this invention are foamable resin compositionscontaining greater than about 1 parts per hundred (pph) and less thanabout 100 pph of the blowing agent composition with respect to resin,preferably greater than about 2 pph and less than about 40 pph, morepreferably greater than about 3 pph and less than about 25 pph, and evenmore preferably greater than about 4 pph and less than about 15 pph ofthe blowing agent composition with respect to resin.

The process for preparing a foamed thermoplastic product is as follows:Prepare a foamable polymer composition by blending together componentscomprising foamable polymer composition in any order. Typically, preparea foamable polymer composition by plasticizing a polymer resin and thenblending in components of a blowing agent composition at an initialpressure. A common process of plasticizing a polymer resin is heatplasticization, which involves heating a polymer resin enough to softenit sufficiently to blend in a blowing agent composition. Generally, heatplasticization involves heating a thermoplastic polymer resin near orabove its glass transition temperature (Tg), or melt temperature (Tm)for crystalline polymers.

A foamable polymer composition can contain additional additives such asnucleating agents, cell-controlling agents, dyes, pigments, fillers,antioxidants, extrusion aids, stabilizing agents, antistatic agents,fire retardants, IR attenuating agents and thermally insulatingadditives. Nucleating agents can include, among others, materials suchas talc, calcium carbonate, sodium benzoate, and chemical blowing agentssuch azodicarbonamide or sodium bicarbonate and citric acid. IRattenuating agents and thermally insulating additives can include carbonblack, graphite, silicon dioxide, metal flake or powder, among others.Flame retardants can include, among others, brominated materials such ashexabromocyclodecane and polybrominated biphenyl ether.

Foam preparation processes of the present invention include batch,semi-batch, and continuous processes. Batch processes involvepreparation of at least one portion of the foamable polymer compositionin a storable state and then using that portion of foamable polymercomposition at some future point in time to prepare a foam.

A semi-batch process involves preparing at least a portion of a foamablepolymer composition and intermittently expanding that foamable polymercomposition into a foam all in a single process. For example, U.S. Pat.No. 4,323,528, incorporated herein by reference, discloses a process formaking polyolefin foams via an accumulating extrusion process. Theprocess comprises: 1) mixing a thermoplastic material and a blowingagent composition to form a foamable polymer composition; 2) extrudingthe foamable polymer composition into a holding zone maintained at atemperature and pressure which does not allow the foamable polymercomposition to foam; the holding zone has a die defining an orificeopening into a zone of lower pressure at which the foamable polymercomposition foams and an openable gate closing the die orifice; 3)periodically opening the gate while substantially concurrently applyingmechanical pressure by means of a movable ram on the foamable polymercomposition to eject it from the holding zone through the die orificeinto the zone of lower pressure, and 4) allowing the ejected foamablepolymer composition to expand to form the foam.

A continuous process involves forming a foamable polymer composition andthen expanding that foamable polymer composition in a non-stop manner.For example, prepare a foamable polymer composition in an extruder byheating a polymer resin to form a molten resin, blending into the moltenresin a blowing. agent composition at an initial pressure to form afoamable polymer composition, and then extruding that foamable polymercomposition through a die into a zone at a foaming pressure and allowingthe foamable polymer composition to expand into a foam. Desirably, coolthe foamable polymer composition after addition of the blowing agent andprior to extruding through the die in order to optimize foam properties.Cool the foamable polymer composition, for example, with heatexchangers.

Foams of the present invention can be of any form imaginable includingsheet, plank, rod, tube, beads, or any combination thereof. Included inthe present invention are laminate foams that comprise multipledistinguishable longitudinal foam members that are bound to one another.

EXAMPLES Examples 1-7 Solubility and Diffusivity of Gases in Polystyrene

The solubility and diffusivity of gases in polystyrene resin wasmeasured using capillary column inverse gas chromatography (cc-IGC) asdescribed in: Hadj Romdhane, Ilyess (1994) “Polymer-Solvent Diffusionand Equilibrium Parameters by Inverse Gas-Liquid Chromatography” PhDDissertation, Dept. of Chem. Eng., Penn State University. and Hong S U,Albouy A, Duda J L (1999) “Measurement and Prediction of Blowing AgentSolubility in Polystyrene at Supercritical Conditions” Cell Polym18(5):301-313.

A 15 m long, 0.53 min diameter GC capillary-column was prepared with a 3micron thick polystyrene internal film coating. The column was installedinto a Hewlet Packard 5890 Series II Gas Chromatograph with flameionizer detector. Elution profiles for gases being tested were analyzedaccording the method outlined in the reference, using methane as thereference gas. The results give the diffusion coefficient of the gasthrough the polymer, Dp, and the solubility of the gas in the polymer interms of the partition coefficient, K, which is the ratio of theconcentration of the gas in the polymer phase to the concentration inthe vapor phase. As such, the greater the value of K for a particulargas in the resin the greater its solubility in that resin.

Table 1 shows the partition coefficient and diffusivity values forseveral gases in polystyrene at 140° C. Comparative examples 1-5 showthe solubility and diffusivity of HCFC-142b(1-chloro-1,1-difluoroethane), HFC-152a (1,1-difluoroethane), HFC-134a(1,1,1,2-tetrafluoroethane), HFC-32 (difluoromethane), and HFC-245fa(1,1,1,3,3-pentafluoropropane) in polystyrene (PS). Examples 6 and showthe solubility and diffusivity of trans-HCFO-1233zd(1-chloro-3,3,3-trifluoropropene) and HCFO-1233xf(2-chloro-3,3,3-trifluoropropene).

These examples show that HCFO-1233zd and HCFO-1233xf have sufficientsolubility and diffusivity in polystyrene resin to be effective blowingagents or as useful coblowing agents with other blowing agents such asHFCs or carbon dioxide. HCFO-1233xf, for instance, was found to have asolubility comparable to that of HCFC-142b. The diffusivities ofHCFO-1233zd and HCFO-1233xf were found to be low, indicating that shouldbe useful in providing foams with improved k-factor.

TABLE 1 Partition Coefficient and Diffusivity of Gases in Polystyrene at140° C. by Inverse Gas Chromatography Bp Mw Dp Example Gas (° C.)(g/mol) K (cm²/s) 1 HCFC-142b −9.8 100.5 1.249 2.61E−08 2 HFC-152a −24.166.05 0.734 9.49E−08 3 HFC-134a −26.1 102.02 0.397 3.40E−08 4 HFC-32−51.7 52.02 0.436 1.95E−07 5 HFC-245fa 15.1 134.05 0.639 2.05E−08 6HCFO-1233zd 20.5 130.5 2.326 1.72E−08 7 HCFO-1233xf 15 130.5 1.4751.67E−08

Examples 8-20

Extruded polystyrene foam was produced using a counter-rotating twinscrew extruder with internal barrel diameters or 27 mm and a barrellength of 40 diameters. The screw design was suitable for foamingapplications. The pressure in the extruder barrel was controlled withthe gear pump and was set high enough such that the blowing agentdissolved in the extruder. The extruder die for examples 9-20 was anadjustable-lip slot die with. a gap width of 6.35 mm. For example 1, thedie was a 2 mm diameter strand die with a 1 mm land length. Two gradesof general purpose polystyrene were used for the extrusion trials andfed to the extruder at rates of either 2.27 or 4.54 kg/hr (5 or 10lb/hr). Blowing agents were pumped into the polystyrene resin melt at acontrolled rate using high pressure delivery pumps. In the extruder, theblowing agent is mixed and dissolved in the resin melt to produce anexpandable resin composition. The expandable resin composition is cooledto an appropriate foaming temperature and then extruded from the diewhere the drop in pressure initiates foaming. Talc was used as anucleating agent and was pre-blended with polystyrene to make amasterbatch of 50 wt % talc in polystyrene. Beads of this masterbatchwere mixed with polystyrene pellets to achieve 0.5 wt % talc in eachexperiment.

The density, open cell content, and cell size was measured for foamsamples collected during each run. Density was measured according toASTM D792, open cell content was measured using gas pychnometryaccording to ASTM D285-C, and cell size was measured by averaging thecell diameters from scanning electron microscope (SEM) micrographs offoam sample fracture surfaces. SEM images are also used to observe thecell structure and qualitatively check for open cell content.

Table 2 shows data for examples 8 through 20, including the loading ofeach blowing agent in the formulation, the resin feed rate, melt flowindex of the resin, the expandable resin melt temperature, and thedensity, cell size, and open cell content of the resulting foamedproduct.

Comparative example 8 is typical for polystyrene foaming with HFC-134a,where the poor solubility and difficulties in processing tend to lead tohigher density foam with smaller size and more open cells. Increasingthe amount of HFC-134a in the formulation above the solubility limit,around 6.5 wt % 134a for this system, was found to lead to many problemsincluding blow holes, defects, foam collapse, large voids, high opencell content, and others.

Comparative examples 9 and 10 show results for foaming with3,3,3-trifluoropene (HFO-1243zf; TFP).

In examples 11 and 12, blowing agent compositions of TFP (HFO-1243zf)and HCFO-1233zd permitted production of lower density foam thanachievable with TFP alone along with a beneficial enlargement in thecell size, where it was possible to produce closed-cell foam productwith cell sizes greater than 0.2 mm at densities less than 53 kg/m³ andeven less than 45 kg/m³. These foams would be useful as thermalinsulating foams with improved k-factor.

Examples 13 through 16 were produced during the same extrusion trial. Inexamples 13, HFC-134a was used as the only blowing agent at a loading of5.3 wt %. The foamed product had significant defects including blowholesand large voids. During foam extrusion there was frequent popping at thedie caused by undissolved blowing agent exiting the die. Followingexample 13, HCFO-1233zd, predominantly the trans isomer, was added toproduce example 14, which resulted in reduction of the popping at thedie with a reduction in the die pressure along with reducing the numberof defects in the foamed product. Then the blowing agent feeds wereadjusted to generate examples 15 and 16, where there was no popping atthe die and only a few defects. The foam of example 13, blown using onlyHFC-134a, had a very broad or bimodal cell size distribution, with cellsizes ranging from around 0.05 mm to around 1 mm, with the larger cellsnear the center of the sample. The foams blown with combinations of 134aand HCFO-1233zd also had non-uniform cell size distributions, with thelarger cells near the core of the samples, but with much narrowerdistributions without the very large cells. HCFO-1233zd improved theprocessing of the 134a blown foams, improved the general quality of thefoamed product, and permitted production of lower density foam.

Examples 17 and 18 were produced during using HFO-1234yf(2,3,3,3-tetrafluoroethane) as the only blowing agent. At a loading of5.7 wt % 1234yf, as shown in example 18, the foamed product had verysmall cell size, macrovoids, blowholes, high open cell content, andfrequent periods of popping at the die caused by undissolved blowingagent. Increasing the content of 1234yf made these problems worse. Forexamples 19 and 20, blowing agent compositions of HFO-1234yf andHCFO-1233zd permitted production of lower density foam than was producedusing the HFO-1234yf alone. The foamed samples of examples 19 and 20were of good quality, with few defects and produced without popping atthe die. The HCFO-1233zd was predominantly the trans-isomer.

TABLE 2 Blowing Agent Loading Polystyrene Resin Foam Properties 134a TFP1234yf 1233zd Feed MFI T

Density Cell Size OCC Example (wt %) (wt %) (wt %) (wt %) (kg/hr) (g/10min) (° C.) (kg/m²) (mm) (%) 8 6.4 — — — 2.27 4.0 111 60.9 0.06 23 9 —6.6 — — 2.27 11.0 114 57.6 0.11 <5 10 — 7.2 — — 2.27 11.0 115 56.5 0.11<5 11 — 4.1 — 6.6 4.54 11.0 113 44.3 0.29 <5 12 — 6.5 — 3.4 4.54 11.0113 52.5 0.35 <5 13 5.3 — — — 4.54 11.0 118 76.5 defects ~10 14 5.0 — —5.0 4.54 11.0 116 49.9 0.05. 0.20 ~10 15 4.4 — — 4.3 4.54 11.0 116 48.00.08. 0.25 ~10 16 4.4 — — 5.0 4.54 11.0 116 45.6 0.09. 0.16 ~10 17 4.4 —4.54 11.0 117 90.9 0.15 5 18 — — 5.7 — 4.54 11.0 115 71.6 0.06 31.4 19 —— 4.2 4.3 4.54 11.0 114 55.2 0.12 <5 20 — — 4.8 5.0 4.54 11.0 113 53.50.08 <5

indicates data missing or illegible when filed

EXAMPLES 21-50

Extruded polystyrene foam was produced using a counter-rotating twinscrew extruder with internal barrel diameters or 27 mm and a barrellength of 40 diameters. The screw design was suitable for foamingapplications. The pressure in the extruder barrel was controlled with agear pump and was set high enough such that the blowing agent dissolvedin the extruder, The extruder die was an adjustable-lip slot die with agap width of 6.35 mm. Two grades of general purpose polystyrene was usedfor the extrusion experiments and fed to the extruder at an overall rateof 4.54 kg/hr (10 lb/hr). Blowing agents were pumped into thepolystyrene resin melt at a controlled rate using high pressure deliverypumps. In the extruder, the blowing agent mixed with and dissolved inthe resin melt to produce an expandable resin composition. Theexpandable resin composition was cooled to an appropriate foamingtemperature and then extruded from the die where the drop in pressureinitiates foaming. Talc was used as a nucleating agent at 0.5 wt % talcin polystyrene.

The density, open cell content, and cell size was measured for foamsamples collected during each run. Open cell content was measured usinggas pychnometry according to ASTM D285-C, and cell size was measured byaveraging the cell diameters from scanning electron microscope (SEM)micrographs of foam sample fracture surfaces, SEM images are also usedto observe the cell structure and qualitatively check for open cellcontent.

Examples 21 to 27 were produced using HFO-1243zf as the only blowingagent at loadings ranging from 4.1 to 8.5 wt %. Examples 24 and 25duplicate examples 9 and 10 above. The results are summarized in Table 3and plotted in FIG. 1.

Examples 28 to 30 were produced using trans-HCFO-1233zd as the onlyblowing agent at loadings ranging from 8.6 to 11.7 wt %. The results aresummarized in Table 3 and plotted in FIG. 1.

Examples 31 to 39 were produced using blowing agent combinations of from38 wt % to 66 wt % HFO-1243zf and from 62 wt % to 34 wt %trans-HCFO-1233zd as the blowing agents. The total loading of blowingagent ranged from 8.2 to 12.5 wt %. Examples 36 and 37 duplicateexamples 12 and 11 above. The results are summarized in Table 3 andplotted in FIG. 1.

Examples 40 to 50 were produced using blowing agent combinations of from33 wt % to 53 wt % HFO-1243zf, 28 wt % to 52 wt % trans-HCFO-1233zd, andfrom 13 wt % to 20 wt % carbon dioxide (CO2). The total blowing agentloading ranged from 7.6 to 11.3 wt %. The results are summarized inTable 3 and plotted in FIG. 1.

The blowing agent formulations for examples 21 to 50 are shown in Table3 along with the foam density and the extrusion melt temperature(Tmelt). With the exception of Examples 30 and 38, all foams shown inTable 3 had an open cell content<10%. Examples 30 and 38 had an opencell content 14 to 15%. All foams were generally of good quality withfew, if any, defects.

FIG. 1 shows a plot of total blowing agent content versus foam densityfor examples 21 to 50. As mentioned above, the data are divided intofour series: 1) Examples 21 to 27 for HFO-1243zf; 2) Examples 28 to 30for tans-HCFO-1233zd; 3) Examples 31 to 39 for combinations ofHFO-1243zf and trans-HCFO-1233zd (1243zf/1233zd); 4) Examples 40 to 50for combinations of HFO-1243zf, trans-HCFO-1233zd, and carbon dioxide(1243zf/1233zd/CO2). The data shows that using the blowing agentcombinations of 1243zf/1233zd or 1243zf/1233zd/CO2 surprisingly permitsthe production of low density foam over a wider range of blowing agentloadings than either 1243zf or 1233zd alone. For example, considerexamples 27 and 28, blown with approximately 8.5 wt % 1243zf and 1233zdrespectively. Examples 31-32 and 40-44, blown with 1243zf/1233zd and1243zf/1233zd/CO2 respectively, are of significantly lower density butblown using about the same amount of blowing agent or less. Also, thefoam of example 27 had a cell size <0.1 min whereas all foams ofExamples 31-32 and 40-44 had cell sizes of from 0.1-0.3 mm.

TABLE 3 Foams blown with 1243zf, 1233zd, CO2 Blowing Agent CompositionBlowing Agent Loading 1243zf 12333zd CO2 1243zf 12333zd CO2 Total TmeltDensity Example (wt %) (wt %) (wt %) (wt %) (wt %) (wt %) (wt %) (° C.)(kg/m³) 21 100%  — — 4.1 — — 4.1 127 84.1 22 100%  — — 4.9 — — 4.9 11970.2 23 100%  — — 5.8 — — 5.8 123 60.7 24 100%  — — 6.6 — — 6.6 114 57.625 100%  — — 7.2 — — 7.2 115 56.5 26 100%  — — 7.2 — — 7.2 122 51.9 27100%  — — 8.5 — — 8.5 125 53.3 28 — 100%  — — 8.6 — 8.6 113 72.2 29 —100%  — — 10.2  — 10.2 113 42.4 30 — 100%  — — 11.7  — 11.7 113 55.5 3165% 35% — 5.3 2.9 — 8.2 117 46.8 32 65% 35% — 5.3 2.9 — 8.2 114 50.6 3349% 51% — 4.6 4.9 — 9.5 122 45.2 34 49% 51% — 4.6 4.9 — 9.5 118 43.2 3549% 51% — 4.6 4.9 — 9.5 114 44.7 36 66% 34% — 6.5 3.4 — 9.9 113 52.5 3738% 62% — 4.1 6.6 — 10.8 113 44.3 38 45% 55% — 5.5 6.2 — 12.1 116 38.339 38% 62% — 4.8 7.7 — 12.5 112 41.8 40 52% 28% 20% 4.0 2.1 1.5 7.6 11446.9 41 53% 29% 19% 4.2 2.3 1.5 8.0 115 48.1 42 53% 29% 18% 4.5 2.4 1.58.4 116 47.6 43 53% 29% 18% 4.5 2.4 1.5 8.4 120 42.9 44 33% 49% 17% 2.94.2 1.5 8.6 123 42.1 45 34% 50% 16% 3.0 4.5 1.5 9.1 115 43.2 46 43% 41%16% 3.9 3.8 1.5 9.2 115 45.8 47 43% 41% 17% 3.9 3.8 1.5 9.2 119 41.9 4834% 50% 16% 3.2 4.8 1.5 9.5 118 41.0 49 34% 51% 15% 3.6 5.3 1.5 10.4 11739.8 50 35% 52% 13% 3.9 5.9 1.5 11.3 121 40.1

Examples 51-62

Examples 51 to 53 were produced using HFO-1234yf(2,3,3,3-tetrafluoropropene) as the only blowing agent at loadingsranging from 4.4 to 6.6 wt %. Examples 51 and 52 duplicate examples 17and 18 above. The results are summarized Table 4 and plotted in FIG. 2.

Examples 54 to 56 were produced using HFC-134a(1,1,1,2-tetrafluoroethane) as the only blowing agent at loadingsranging from 5.0 to 5.8 wt % and are typical of foams produced usingHFC-134a with this extrusion system. The results are summarized in Table4 and plotted in FIG. 2.

Examples 57 and 58 were produced using a combination of 49 wt %HFO-1234yf (2,3,3,3-tetrafluoropropene) and 51 wt % trans-HCFO-1233zd(E-1-chloro-3,3,3-trifluoropropene) as the blowing agents at totalloadings of 8.5 wt % and 9.8 wt % respectively. Examples 57 and 58duplicate examples 19 and 20 above. The results are summarized in Table4 and plotted in FIG. 2.

Examples 59 to 62 were produced using combinations of from 47 wt % to 51wt % HFC-134a and from 53 wt % to 49 wt % trans-HCFO-1233zd as theblowing agents at total loadings of 8.6 wt % and 10.0 wt %. Examples 60to 62 duplicate examples 14 to 16 above. The foams were all of goodquality with few defects. The results are shown in Table 4 and plottedFIG. 2.

The results shown in Table 4 and FIG. 2 show the surprising andunexpected benefits of using HCFO-1233zd as a coblowing agent incombination with other blowing agents, particularly those with lowersolubility in the resin such as HFO-1234yf and HFC-134a.

TABLE 4 Foams blown with 1234yf, 134a, 1233zd Blowing Agent CompositionBlowing Agent Loading 1234yf 134a 1233zd 1234yf 134a 1233zd Total TmeltDensity OCC Example (wt %) (wt %) (wt %) (wt %) (wt %) (wt %) (wt %) (°C.) (kg/m³) (%) 51 100% — — 4.4 — — 4.4 117 90.9 <10 52 100% — — 5.7 — —5.7 115 71.6 31 5 100% — — 6.6 — — 6.6 115 74.3 15 54 — 100%  — — 5.3 —5.3 115 76.5 <5 55 — 100%  — — 5.0 — 5.0 127 74.9 <5 56 — 100%  — — 5.8— 5.8 112 63.4 14 57  49% — 51% 4.2 — 4.3 8.5 114 55.2 <5 58  49% — 51%4.8 — 5.0 9.8 113 53.5 <1 59 — 50% 50% — 4.2 4.3 8.6 114 48.35 <10 60 —51% 49% — 4.4 4.3 8.7 116 48.0 <10 61 — 47% 53% — 4.4 5.0 9.4 116 45.6<10 62 — 50% 50% — 5.0 5.0 10.0 116 49.9 <10

Comparative Examples 63-65

Comparative examples 63 to 65 were produced using combinations ofHFC-134a and HFO-1243zf (3,3,3-trifluoropropene) as the blowing agents.Examples 63 and 64 were produced using a blowing agent combination with36 wt % HFO-1243zf and 64 wt % HFC-134a and total blowing agent loadingsof 6.4 wt % and 4.8 wt % respectively. Example 65 was produced usingequal parts by weight of HFO-1243zf and HFC-134a at a total blowingagent loading of 5.0 wt %. The foam of example 63, produced using thehighest blowing agent loading of this series of samples, had a verysmall foam cell size and noticeable defects. Surprisingly this is incontrast to examples 59 to 62 produced using combinations of HFC-134awith trans-HCFO-1233zd, which were relatively defect free and of goodquality, lower density, and lower open cell content. These examples showthe benefit of using the HCFOs of the present invention as coblowingagents over HFOs as coblowing agents. The results are shown in Table 5and plotted in FIG. 3.

TABLE 5 Foams blown with 1243zf, 134a Blowing Agent Composition BlowingAgent Loading 1243zf 134a 1243zf 134a Total Tmelt Density OCC Example(wt %) (wt %) (wt %) (wt %) (wt %) (° C.) (kg/m³) (%) 63 36% 64% 2.3 4.06.4 110 71.9 14 64 36% 64% 1.7 3.0 4.8 116 74.2 <10 65 50% 50% 2.5 2.55.0 118 63.5 <10

The examples shows that the combination of the present inventionprovides foam forming mix that processes acceptably and which producesfoam of commercially acceptable cell size and density while thecomponents individually do not produce commercially acceptable foamand/or have processability problems. It was surprising and unexpectedthat the combination of blowing agents that did not produce acommercially acceptable foam were able to produce a commerciallyacceptable foam when used in combination.

Although the invention is illustrated and described herein withreference to specific embodiments, it is not intended that the appendedclaims be limited to the details shown. Rather, it is expected thatvarious modifications may be made in these details by those skilled inthe art, which modifications may still be within the spirit and scope ofthe claimed subject matter and it is intended that these claims beconstrued accordingly.

1. A foam product comprising: a thermoplastic foam material selected from the group consisting of polystyrene, polyethylene, polypropylene, or mixtures thereof; and a blowing agent comprising a hydrochlorofluoroolefin selected from the group consisting of 1-chloro-3,3,3-trifluoropropene, 2-chloro-3,3,3-trifluoropropene, or mixtures thereof and a hydrofluorocarbon coblowing agent selected from 1,1,1,2-tetrafluoroethane, 3,3,3-trifluoropropene, 2,3,3,3-tetrafluoropropene or mixtures thereof; wherein said foam product exhibits a density below 50 kg/m³ and an open cell content of 10% or less at a blowing agent loading of from 8 to 10 wt %.
 2. The foam product of claim 1 further comprising a second coblowing agent selected from non-hydrochlorofluoroolefin hydrofluoroolefin, an alkane, carbon dioxide, an atmospheric gas, an inert gas, and mixtures thereof.
 3. The foam product of claim 1 wherein said 1-chloro-3,3,3-trifluoropropene contains greater than 75 wt % of the trans-isomer.
 4. The foam product of claim 2 wherein said non-hydrochlorofluoroolefin hydrofluoroolefin is selected from C3 through C5 fluorinated alkene or mixtures thereof.
 5. The foam product of claim 4 wherein said fluorinated alkene is selected from tetrafluoropropene, pentafluoropropene, or mixtures thereof.
 6. The foam product of claim 5 wherein said tetrafluoropropene is selected from cis-1,3,3,3-tetrafluoropropene; trans-1,3,3,3-tetrafluoropropene; 2,3,3,3-tetrafluoropropene, or mixtures thereof.
 7. The foam product of claim 5 wherein said pentafluoropropene is selected from cis-1,2,3,3,3-pentafluoropropene; trans-1,2,3,3,3-pentafluoropropene, or mixtures thereof.
 8. The blowing agent composition of claim 2 wherein said alkane is selected from propane, butane, pentane, hexane, or mixtures thereof.
 9. The foam product of claim 8 wherein said pentane is selected from n-pentane, cyclopentane, iso-pentane or mixtures thereof.
 10. The foam product of claim 1 further comprising an alcohol.
 11. The foam product of claim 10 wherein said alcohol is selected from ethanol, iso-propanol, propanol, butanol, ethyl hexanol, methanol, or mixtures thereof.
 12. The foam product of claim 1 further comprising an ether.
 13. The foam product of claim 12 wherein said ether is selected from dimethyl ether, diethyl ether, methylethyl ether, or mixtures thereof.
 14. The foam product of claim 1 further comprising a ketone.
 15. The foam product of claim 14 wherein said ketone is selected from acetone, methyl ethyl ketone, and mixtures thereof.
 16. The foam product of claim 1 further comprising dyes, pigments, cell-controlling agents, fillers, antioxidants, extrusion aids, stabilizing agents, antistatic agents, fire retardants, IR attenuating agents, thermally insulating additives, plasticizers, viscosity modifiers, impact modifiers, gas barrier resins, carbon black, surfactants, and mixtures thereof. 